Transmission and receipt of signals.



No. 727,325. PATENTED. MAY 5, 1903.

R. A. FBSSENDEN. TRANSMISSION AND RECEIPT OF SIGNALS.

APPLICATION FILED JUNE 2, 1900.

N0 MODEL. 3 SHEETS-SHEET 1.

PATE-NTED. MAY5, 190-3.

R. A. PESSENDEN. TRANSMISSION AND RECEIPT OF SIGNALS.

APPLICATION FILED JUNE 2, 1900.

8 SHEETS-SHEET 2.

N0 MODEL.

WIT E9 5 2 No. 727,325. I PATENTED MAY 5, 1.903. R. A. FESSENDEN.

TRANSMISSION AND RECEIPT OF SIGNALS. APPLICATION- FILED JUNE 2, 1900. N0 MODEL. a SHEETS-$112111 a.

a S I I a I WITNESSES: NVENTOR 551% 5 U HQMLLDM m: uonms runs :0. Pnmuumu, wAsHmomm-u c,

Patented May 5, 1903.

Um'ran STATES ATENT FFIGE.

REGINALD A. FESSENDEN, OF ALLEGHENY, PENNSYLVANIA.

TRANSMISSION AND RECEIPT OF SIGNALS.

SEECIFICATION formingpart of Letters Patent No. 727,325, dated May 5, 1903.

Application filed June 2, 1900. Serial No. 18,878. (No model.)

To all whom it may concern.-

Be it known that I, REGINALD A. FESSEN- DEN, a citizen of the United States, residing at Allegheny, in the county of Allegheny and State of Pennsylvania, have invented or discovered certain new and useful Improvements in the Transmission and Receipt of Signals, of which improvements the following is a specification.

The invention described herein relates to certain improvements in the selective transmission and receipt of wireless messages or signals.

In the system of wireless telegraphy now in use difficulty is experienced in the selection of messages or signals. This difficulty arises from the fact that when magnetic waves are generated from one point they move equally in all directions and will be received at all stations reached by the waves.

The object of the present invention is to provide for the generation at the sendingstation in varying order of two or more series of magnetic waves or electrical impulses, the waves or impulses of each of the series differing from those of the other series, the selective reception and transformation or utilization of each of the different series, and, finally, the recording at each receiving-station of only such series of waves or impulses as are sent in a particular order. The selective reception of the differing series is obviously necessary and in the apparatus shown is secured by tuning or harmonizing various parts of the receiving system to the characteristic period of the particular series of energy fluctuations whereby they are designed to be actuated.

The invention is hereinafter more fully described and claimed.

In the accompanying drawings, forming a part of this specification, Figure 1 is a diagrammatic view illustrating my improved system of generating and receiving magnetic waves. Figs. 2 and 3 illustrate the mechanism employed at the receiving-stations. Figs. 4, 5, and 6 are details views of the mechanismemployed at the sending or generating station. Fig.7 is a diagrammatic viewillustrating the application of my improvement to systems employing a wire or other conductor for the transmission of the electrical im-.

pulses, and Fig. 8 illustrates a form of receiving mechanism and one of the parallel branch circuits.

In the practice of my invention a series of two or more vertical generating-wires or generating-surfaces 5 5*, &c., are connected at the sending-station A to a series of two or more terminals or knobs 4 4", &c., ofa series of two or moreinduction-coils 1 l", &c. The secondary coils are connected, as usual, to both discharge terminals or knobs of the inductions and also to ground. The primary coils of the inductions are each included in circuits of a generator or series of generators 2, and in each such circuit is included a circuit make and break mechanism. This part of the apparatus need not be more fully described, since it may be such as I have described in my Patent No. 706,735, August 12', 1902. A convenient form of make-and-break mechanism is shown in Figs. 1, 4, and 5 and consists of metal disks 3 3*, & c., dependent upon the number of generating or sending wires employed, mounted upon a shaft 20, but preferably insulated from each other by disks 21, of insulating material. The shaft 20, which is rotated at a constant speed by a driving device (indicated at 20) of any suitable construction, is electrically connected to one pole of the generator 2, and the disks 3 3 which are in electrical contact with the shaft, are provided with shoulders or knobs 22, adapted when the disks are shifted to strike against plates 23 23", &c., connected to the opposite pole of the generator 2. The disks 3 3", 850., are adjustably held in position on the shaft by suitable means such, for example, as that shown in Fig. 4, consisting of a shoulder on the shaft and a nut screwing onto the shaft, whereby the disks may be clamped in any desired position. By the rotation of the shaft the circuits of the generator will be made and broken in any desired order or interval of time, dependent on the adjustment of the disks around the shaft and the speed of rotation of the shaft. The rate of rotation is not important provided it be constant and not too low. It must be constant in order to avoid various objectionable, if not insuperable, complications in the receiving apparatus, for the said rate must bear a fixed ratio to the rate of movement of the tape at the receiving-station. As the periodicity of magnetic Waves is dependent upon the self-induction -/capacity,and as selfinduction and capacity of the sending-wires varies with the length and the diameter of the wires, the latter are so proportioned relative to each other, as by varying their lengths, that the periodicity of the Waves generated by one wire will differ from that of the waves generated by the other Wires. By adjusting the disks 3 3", &c., on the shaft the series of waves may be sent out in any desired order 1'. e., a b c d, these letters designating the waves discharges, respectively, from wires 5*, 5", 5, and 5 The receiver comprises a series of selective collecting-wires or other suitable surfaces 6, 6 6 and 6, &c., projecting upward preferably vertically, though they may be somewhat inclined. These collecting-wires equal in number and are respectively electrically equivalent in height to the corresponding discharging or radiating wires 5 5*, &c., at the sending-stationthat is to say, corresponding radiating and receiving or collecting wires forming a pair are electrically tuned to each other, and the tuning or equality of time period of free electrical oscillation may be brought about by making the electrical constants of the two either equal or equivalent, as by changing the length or surface of one of them. They are obviously equivalent when the quantity represented by capacity X Vmdnctance is the same for each member of a pair. The mechanisms controlled by the voltages or currents induced in the receiving-wires or operated directly thereby are also tuned to the period characteristic of the energy fluctuations to which they are sub jected in accordance with practices and rules well known in the art, so that the recording mechanism connected with each receivingwire will be acted on or controlled only by the voltages or currents induced by the corresponding wire at the sending-station, the characteristics of the induced voltages varying with respect to their periodicities in the sense that the periodicities characteristic of a given sending-wire though constant differ from those of any otheras, for example, the recording mechanism connected to the receiving-wire 6 will not be acted on or controlled by any voltages or currents other than those induced by magnetic waves having the characteristics of those generated by the sending-wire 5.

It is sufficiently obvious that in tuning the above-mentioned elements of a single selective receiving system the particular element tuned must be tuned to the frequency of the periodic flux to which it is subjected and that the specific well-known practices and rules adopted will be such as the nature of the case demands. Thus in tuning a collecting receiver-wire to the frequency of the oscillations of the corresponding transmitting system electrical tuning by properly-proportioned inductance and capacity is specified. The cases of mechanism controlled by voltagesorcurrentsinducedin the receiving-wire and the case of mechanism operated by such voltages or currents are referred to hereinafter.

Any suitable form or construction of mechanism may be employed for recording the signals or electrical impulses receivedas, for example, in Fig. 1 coherers 24 2%", &c., are arranged in the circuits of the receiving-wires, which are grounded. These coherers are also included, as is customary, in circuits 25 25*, &c., from a generator or generators 26, said circuits also including portions of the recording mechanism. Generally stated, the recording mechanism consists of a series of two or more electrically-actuated devices which by their combined action will give an audible or visible indication, said devices being either controlled or operated by the voltages or currents induced by the magnetic waves, either directly or by being included in a circuit or circuits that is controlled by such induced voltages or currents, so that all such devices must be operated or the circuits completed in a certain predetermined order corresponding to the order in which the circuits of the generator at the sending-station are made and broken to produce an indication or signal by the indicating instrument. Tuning of the coherers has not been attempted; but in lieu of coherers mechanism may be employed for transforming the current or voltages induced by the magnetic waves into energy of motion, as shown and described in Letters Patent No. 706,735, granted to me August 12, 1902. In Fig. 2 is shown a form of such mechanism, which consists of a coil 7 in series with the receiving-wire 6 and a ring or element 8 so supported in the coil that a plane at right angles to the axis of the ring or element will be at an angle of approximately forty-five degrees l-5) with a plane at right angles to the axis of the coil. This ring is balanced on knife-edges or supportingrods 13, one of which is formed of a good electrical conductor, as silver, the ring or element being preferably formed of aluminium, silver, or other good conductor. A carbon block 14 is so arranged that a portion of the ring will normally restlightlythereon. This microphoneticcontact, the element 8, and the conducting pivotal support 13 for the latter form parts ofa circuit from agencrator 15. While the indicating or regulatingmechanism maybe directly controlled or operated by the circuit of the generator 15, it is preferred to include in the circuit of the generator'15 relay 42, which in turn controls a circuit controlling or operating the indicating or recording mechanism. This apparatus is a very sensitive form of microphonic relay, and the ring 8 being the mechanism or mechanical element directly operated by the voltages or currents induced in the connected tuned receiving-wire should be tuned to the period of the flux to whichit is subjected by following the principles and practices commonly employed in connection with relay apparatus of this delicate typet'. e., by making the time period of mechanical oscillation equal the time period of the flux. This may be done in any convenient way, as by adjusting the extent of projection or the weight or the elasticity of the unsupported side of the ring after the manner of the well-known wire loop of Evershed. Obviously the time period of the flux to which the ring is tuned is necessarily the time period of a train of waves and not the time period of a single wave or oscillation. This is necessarily so, because all displacements of the ring are in the same direction during all the period of continuous-wave activity, and reaction to normal can only take place during discontinuities of the wave-trains.

A convenient form of mechanism for receiving indications is illustrated in Figs. 1, 2, and 3. This mechanism consists of a bed 28, over which is drawn a band or strip 29, of paper or other flexible non-conducting material. The strip is drawn from a spool 30 by a drum 3l, driven at a regular speed by clockwork or other suitable driving mechanism. Aseries of perforating mechanisms dependent on the number of receiving-wires 6 6 dad, are arranged in such relation to the strip of paper that when actuated as hereinafter described the paper will be perforated. YVhile any form of electrically-controlled mechanisms may be employed, that shown in Figs. 2 and 3 is convenient for the purpose. Each of these mechanisms consists of a lever 32, having a punch at one end and having its opposite end attached to the armature of an electromagnet 33,which is included in the circuit controlled by the coherer or by the circuit of generator 15. As each of the coherers is rendered conductive the perforating mechanism included in the eircuittherewith will be operated and a hole formed through the strip. As the operation of the perforators corresponds in succession to the successive operations of the circuit make and break mechanism at the sending-station and as the strip is in constant uniform motion, it follows that the relative positions of the perforations in the strip will correspond to the relative times of operation of the makeand-break mechanisms. As the paper strip moves along the bed it will pass over metal bands 3 L 3?, &c., and under contact springs or brushes 35 35 the, in line with the bands. These bands arearranged in the several paths of movementof the perforations, so that the springs or brushes will contact with the bands as the perforated portions pass between them. These brushes are adjustably supported so that they can be positioned in accordance with the consecutive operation of the make-and-break mechanisms at the sending-station. When so adjusted,

they will all be in contact with their respec-' and adjustedcan receive intelligible indieations. It is also necessary that the sequence of operation of the receiving mechanism should correspond to that of the sending mechanism and also that the time interval between the operations of the elements of the receiving mechanism should correspond to the time interval between the successive operations of the elements of the sending mechanism. In other words, to produce a dot or a dash or any other signal or indication at the receiving-station requires the conjoint action of waves from all the sending-wires and consequent operation of each and all the receiving mechanisms. In the form of apparatus shown the shaft 20 must be rotated to complete all the circuitsfrom thegenerator 2, so

stood that although all of the perforations may be operated by waves from other sources if the perforations are not in the predetermined order a closure of the circuit of the indicator Will beeffected.

It will be observed that the recording mechanism shown and described is, in effect, acir chit-closing mechanism whose parts or elements cooperate to effect a closure of the signaling or indicating circuit and are controlled by currents or voltages induced by magnetic waves generated at the sending-station.

As will be understood by those skilled in the art, a moving strip normally non-conductive, but capable of being rendered conduct ive by the action of an electric current or other electrically-controlled means, may be employed, the perforating mechanisms being replaced by mechanisms known in the art for rendering portions conductive.

As the Wires or surfaces 5 5", 850., at one station are employed both for generating and" receiving the magneticwaves as signals are sent or received, the indicating or receiving mechanism and the generating mechanism are connected to said wires or snrfaces,"as In order to protect the in shown in .Fig. 1. dicating or receiving mechanism when sending messages, a switch mechanism is inter posed between the wires or surfaces 5 5 &c., and the indicating mechanism. A convenient form or construction of such switch consists of a cylinder 43, of insulating material, mounted on the shaft 20, and metal springs 44, bearing on the shell. Metal bands 45 are placed on the cylinder in line with the springs 44, said bands extending around the cylinder except for a distance a little greater than the peripheral length of the knobs 22 on the disks 3 of the circuit-breaker. The bands 45 are so arranged that the springs 44 will not be in contact with the bands when the knobs 22 are in contact with the plates 23. In lieu of entirely breaking the circuits of the coherers shunt-circuits 46, having suitable resistances, are arranged around the switch mechanism.

The character of the waves generated by the surfaces or wires can be varied by increasing the heights or diameters of the wires, thereby increasing the generating area. The character of the waves can also be varied by connecting to the wire or wires a condenser or capacity, as at as, or a self-inductance in the, form of a coil, as at y.

As shown in Fig. 7, myimprovement is applicable to the sending and receiving of signals through wires or other conductors. At the sending-station a series of two or more generators 46 46", &c., constructed to generate currents of diflerent periodicities, are connected to the terminals 47 47*, &c., of a make-and-break mechanism. These terminals, which may be formed by springs, are constructed and arranged so that they will be normally out of contact with disks 48 48*, &c., which are mounted on the shaft 49 and in electrical contact therewith, but insulated from each other. The shaft 49 is electrically connected to the line-wire 50, extending to another station, where the line-wire is connected to a series of two or more recording mechanisms 51 51 850., each mechanism being tuned so as to be actuated only by a current of a certain periodicity. Any construction of mechanism suitable for the purpose may be employed at the receiving-stationsuch, for example, as that shown in Figs. 2 and 3. When used for recording signals transmitted over a conductor, each of the magnets 33 33*, &c., is connected to the line-wire and to ground or return wire and is constructed or arranged in accordance with rules well known in the art, so as to be responsive only to currents of certain predetermined periodicity, which in the absence of any element corresponding to the coherer or microphonic relay of the wireless system may be the periodicity of the current generated by one of the generators 46 46", &c.

As will be obvious to one skilled in the art, amagnet, such as 33*, ora mechanism, such as 51, or the ring 8 cannot well be tuned as directed in any other way than in accordance with the practices well known in the art of harmonic reed telegraphy, the fundamental principle of which involves a vibrating member whose natural period of mechanical oscillation is the same as that of the periodic flux bywhich it is actuated. It will be equally obvious that though a magnet or mechanism cannot well be tuned by the other method that is, by electrical tuningsomewhat similar functions may be served by tuning its supply-circuit to the period of the impressed flux by suitably proportioning theinductance and capacity of such circuit after the manner shown in Fig. 8, where one of the selective branches is shown tuned to the desired period by the addition of a condenser of proper capacity and where necessary an additional inductance-coil. As will be understood, the function of any tuning is, primarily, the syntonic cumulative action of successive periodic fluxes or manifestations of energy, producing in the syntonic receiving apparatus a maximum instantaneous mechanical or electrical displacement greater than could be produced by any one of said fluxes or energies separately, and, secondarily, selectivity of the energy of the predetermined single frequency to which the receiver must be syntonized. Where the available power is ample, the primary function is subordinate; but in wireless telegraphy it is very important.

In lieu of the mechanism shown in Figs. 2 and 3 a series of siphon-recorders may be employed. In such case the magnets 52 of such mechanisms would be tuned so as to be responsive only to such electrical impulses as have a certain periodicity. This apparatus of Figs. 2 and 3 necessarily includes the self-restoring wave-responsive microphonic relay, and the flux to which the magnets 52 must be tuned is a battery-flux corresponding in frequency to the time period of succession of the wave-trains and not to the time period of the waves forming the train. The time period of the trains of waves is very much lower than the time period of the waves and corresponding to a secondary frequency of a lower order than the other. For this 'reason it is possible to tune the electromagnetic coil 52 in either of the ways described in connection with Figs. 7 and 8that is, by directly tuning the magnet mechanism by the mechanical expedients of reed harmonic telegraphy or indirectly by tuning the circuit in which it is placed, as by the condenser and auxiliary inductance of Fig. 8.

I have mentioned specific ways in which the collecting receiving-wire, the mechanisms acted upon directly by the voltage or currents induced in the receiving-wire, and the mechanism or coils controlled indirectly thereby through a microphonic relay (acted on directly by battery fluctuations) may all be tuned to the period of the flux by which they are actuated; but I do not limit myself to any one of the specific ways mentioned, for it is obvious that the application of any of the practices and rules commonly employed to accomplish similar results would be within the spirit of my invention; neither do I limit myself as to the number of tuned elements to be employed, though it is obviously desirable to tune all three of those mentioned, particularly where the coils 1 1*, &c., have independent interrupters, for in that case the rings 8 may be tuned to the periods of such interrupters and the electromagnetic coils 52 to the periods of the interrupters 3 3 the.

As the receiving mechanism is so constructed as to be responsive only to electrical impulses of certain predetermined periodicity and sent out in a certain predetermined order or with a certain predetermined time interval, it will be readily understood by those skilled in the art that a large number of sending instruments and a corresponding number of receiving instruments may be connected to the same line-wire, so that a large nu inher of signals may be transmitted practically simultaneously without any liability of confusion or mixing up of signals. It is characteristic of my improved method that each signal or indication is formed by the conjoint action of two or more waves or impulses differing in periodicities.

W'hile I have described and shown with some particularity mechanism for the practice of my improved method of signaling, no claim is made herein to such mechanism, as the same forms the subject-matter of another application, Serial No. 53,441, filed March 29, 1901.

I claim herein as my invention 1. As an improvement in the art of signaling by electromagnetic Waves, the method described herein, which consists in generating electromagnetic waves of a predetermined electrical frequency in groups of a predetermined frequency lower than the frequency of the Waves forming said groups and producing indications or signals at the receivingstation by selecting groups of the predetermined frequency, substantially as set forth.

2. As an improvement in the art of signaling by electromagnetic waves, the method herein described which consists in generating electromagnetic waves of a predetermined frequency in groups of apredetermined group frequency lower than that of the waves, and producing signals or indications at the receiving-station by selecting groups of the predetermined group frequency, consisting of waves of the predetermined wave frequency.

3. As an improvement in the art of signaling by electromagnetic waves, the method herein described, which consists in generating electromagnetic waves ofapredetermined electrical frequency in groups of a predetermined frequency lower than the frequency of the waves forming said groups and producing indications or signals at the receiving-station by selecting electrically groups of a predetermined frequency, substantially as set forth. V

l. As an improvement in the art of signaling by electromagnetic waves, the method herein described, which consists in generatin g electromagnetic waves of a predetermined electrical frequency in groups of a predetermined frequency lower than the frequency of the waves forming said groups and producing indications or signals at the receiving-station by selecting mechanically groups of a predetermined frequency, substantially as set forth. v

5. As an improvement in the art of signaling by electromagnetic waves, the method described herein, which consists in generating electromagnetic waves of a predetermined electrical frequency in groups of a predetermined frequency lower than the frequency'of the waves forming said groups and producing indications or signals at the receiving-station by selecting electrically and mechanically groups of a predetermined frequency, substantially as set forth.

6. As an improvement in the art of signaling by electromagnetic waves, the method herein described which consists in generating electromagnetic waves of a predetermined frequency in groups ofa predetermined group frequency lower than that of the waves, and producing signals or indications at the receiving-station by selecting electrically waves of a predetermined wave frequency, and selecting electrically groups formed of such electrically-selected waves and of the predetermined frequency, substantially as set forth.

7. As an improvement in theart of signal-,

ing by electromagnetic waves, the method herein described, which consists in generating electromagnetic waves of a predetermined frequency in groups of a predetermined group frequency lower than that of the waves, and producing signals or indications at the receiving-station by selecting electrically waves of a predetermined wave frequency, and selecting electrically and mechanically groups formed of such electrically-selected waves and of the predetermined frequency, substanconstantly-receptive,Wave-responsive device,

substantially as set forth.

9. As an improvement in the art of signaling by electromagnetic waves, the method described herein, which consists in generating electromagnetic waves of a predetermined electrical frequency in groups of a predetermined frcquency lower than the frequency of the waves forming said groups, and operating by selected groups of the predetermined frcquency a receiving mechanism actuated by a current-operated Wave-responsive device,substantially as set forth.

10. As an improvement in the art of multiple signaling, the method which consists in generating electromagnetic radiation having three or more predetermined frequencies, one at least of these frequencies being a group frequency and lower than the wave frequency, and operating by the conjoint action of two or more of the frequencies, one at least of these being a group frequency, a single receiving mechanism selective of at least one of the group frequencies.

11. As an improvement in the art of multiple signaling, the method, which consists in generating electromagnetic waves of one or more wave frequencies in groups of one or more group frequencies, and operating thereby a series of two or more receiving mechanisms responsive to a group frequency and to a Wave frequency, but not responsive to the same combination of group frequency and wave frequency.

12. As an improvement in the art of signaling, the method herein described, which consists in generating electrical impulses of different periodicities, controlling their order of succession by means of a uniformly-moving commutator, actuating or controlling by such impulses receiving mechanisms tuned to the periodicities controlling or actuating them and producing an indication on a uniformly-moving surface by the conjoint action of the receiving mechanisms.

13. As an improvement in the art of wireless transmission of energy for the purpose of producing a desired effect or indication, the method which consists in generating a succession of electromagnetic Waves, said succession of waves being characterized by a plurality of predetermined periodicities of different orders including a predetermined char acteristic high frequency and a predetermined characteristic secondary frequency of a lower order, emitting or radiating the thus characterized succession of electromagnetic waves, absorbing the same in a receiving surface or wire thereby inducing therein a succession of periodic voltage or current variations of corresponding characteristic frequencies of different orders, causing a succession of voltage or current variations of the secondary or lower order of frequency, to act on a receiving apparatus tuned to said frequency thereby producing cumulative electrical or mechanical displacement and finally utilizing such displacement to cause or control the production of the desired effect or indication.

14:. As an improvement in the art of wireless transmission of energy for the purpose of producing a desired effect or indication, the method which consists in generating a succession of electromagnetic waves, said succession of waves being characterized by a plurality of predetermined periodicities of different orders including a predetermined characteristic high frequency and a predetermined characteristic secondary frequency of a lower order, emitting or radiating the thuscharacterized succession of electromagnetic waves, absorbing the same in a receiving surface or wire thereby inducing therein a succession of periodic "oltage or current variations of corresponding characteristic frequencies of different orders, causing a succession of voltage or current variations of the secondary or lower order of frequency, to act on a cumulative responsive receiving apparatus thereby producing a cumulative effect and finally utilizing such cumulative effect to cause or control the production of the desired effect or indication.

In testimony whereof I have hereunto set my hand.

REGINALD A. FESSENDEN.

Witnesses:

F. E. GAITHER, DARWIN S. WOLCOTT. 

